1. Field of the Invention
The present invention relates to an image processing apparatus and a control method for the same.
2. Description of the Related Art
As technology for controlling the image quality of video captured by a digital video camera or the like, there is known to be technology for setting a predetermined area (detection area) in a video, calculating an evaluation value from the video signal in the detection area, and performing image quality control based on the evaluation value. In one specific known example, an exposure evaluation value related to the exposure condition of the video in the detection area is calculated, and exposure control is performed based on the exposure evaluation value. Other known examples include focus control based on a focus evaluation value related to the focus condition of the video in the detection area, white balance control based on a color evaluation value related to colors in the video in the detection area, and anti-shake control based on a motion vector evaluation value related to a motion vector in the video in the detection area.
Although the method for setting the detection area and the method for calculating the evaluation value differ depending on the type of evaluation value, in general, multiple detection areas are set. The evaluation value for a specified detection area does not always appropriately reflect the condition of the whole area of the video, but it can be expected that setting multiple detection areas will allow evaluation values as a whole to more appropriately reflect the condition of the whole area of the video.
Recent years have seen advances in the development of televisions with resolution higher than high-definition, typified by 4 K×2 K, and the development of high-resolution imaging elements, which have been accompanied by the development of video signal processing technology that takes the increase of video resolution into consideration. As one example, there is known to be technology for dividing a video signal into multiple areas, and processing the video signals of the areas in parallel using multiple signal processing units (Japanese Patent Laid-Open No. 2003-6631).
In the case where a video in which a detection area has been set is divided into multiple areas, and the video signals of the areas are processed in parallel using multiple signal processing units according to conventional technology, there is the possibility of a detection area spanning more than one of the divided areas. Calculating an evaluation value for a detection area that spans multiple areas requires multiple signal processing units to perform calculation in cooperation, thus requiring data to be transferred between the signal processing units and requiring a memory or the like for such data transfer. This can consequently cause problems such as an increase in processing time and a rise in cost. Such problems are not limited to video, and can also arise when calculating an evaluation value for a detection area set in a still image.